From: Peter Zijlstra <peterz@infradead.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"naveen.n.rao@linux.vnet.ibm.com"
<naveen.n.rao@linux.vnet.ibm.com>,
"mbenes@suse.cz" <mbenes@suse.cz>
Subject: Re: [RFC][PATCH] ftrace,objtool: PC32 based __mcount_loc
Date: Fri, 17 Jun 2022 14:06:34 +0200 [thread overview]
Message-ID: <YqxuSgj3DEACVukJ@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <5c759021-99ce-7633-699d-49b3229df339@csgroup.eu>
On Fri, Jun 17, 2022 at 11:44:49AM +0000, Christophe Leroy wrote:
>
>
> Le 17/06/2022 à 13:24, Peter Zijlstra a écrit :
> >
> > Hi,
> >
> > I recently noticed that __mcount_loc is 64bit wide, containing absolute
> > addresses. Since __mcount_loc is a permanent section (not one we drop
> > after boot), this bloats the kernel memory usage for no real purpose.
>
> I guess you mean it is 64bit wide on 64 bits architectures ? Because it
> seems to be defined as 'long' so will be 32bit on 32 bits architectures ?
Right, it's an absolute address in the native size. Clearly I'm somewhat
64bit biassed :-)
next prev parent reply other threads:[~2022-06-17 12:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-17 11:24 [RFC][PATCH] ftrace,objtool: PC32 based __mcount_loc Peter Zijlstra
2022-06-17 11:40 ` Mark Rutland
2022-06-21 16:27 ` Ard Biesheuvel
2022-06-23 14:19 ` Mark Rutland
2022-06-22 14:54 ` Steven Rostedt
2022-06-23 14:21 ` Mark Rutland
2022-06-24 0:01 ` Steven Rostedt
2022-06-17 11:44 ` Christophe Leroy
2022-06-17 12:06 ` Peter Zijlstra [this message]
2022-06-17 20:11 ` Josh Poimboeuf
2022-06-20 7:35 ` Peter Zijlstra
2022-06-20 7:42 ` Christophe Leroy
2022-06-22 14:50 ` Steven Rostedt
2022-06-24 7:16 ` Peter Zijlstra
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